serial: 8250: export get_mctrl function

Exposes get_mctrl() function so that it can be overriden with platform
specific implementation.
Signed-off-by: Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_core.c

@@ -830,6 +830,7 @@ static int serial8250_probe(struct platform_device *dev)
 		uart.port.handle_irq	= p->handle_irq;
 		uart.port.handle_break	= p->handle_break;
 		uart.port.set_termios	= p->set_termios;
+		uart.port.get_mctrl	= p->get_mctrl;
 		uart.port.pm		= p->pm;
 		uart.port.dev		= &dev->dev;
 		uart.port.irqflags	|= irqflag;
@@ -1022,6 +1023,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
 		/*  Possibly override set_termios call */
 		if (up->port.set_termios)
 			uart->port.set_termios = up->port.set_termios;
+		if (up->port.get_mctrl)
+			uart->port.get_mctrl = up->port.get_mctrl;
 		if (up->port.set_mctrl)
 			uart->port.set_mctrl = up->port.set_mctrl;
 		if (up->port.startup)

drivers/tty/serial/8250/8250_port.c

@@ -1882,7 +1882,7 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)
 	return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0;
 }
 
-static unsigned int serial8250_get_mctrl(struct uart_port *port)
+unsigned int serial8250_do_get_mctrl(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	unsigned int status;
@@ -1903,6 +1903,14 @@ static unsigned int serial8250_get_mctrl(struct uart_port *port)
 		ret |= TIOCM_CTS;
 	return ret;
 }
+EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl);
+
+static unsigned int serial8250_get_mctrl(struct uart_port *port)
+{
+	if (port->get_mctrl)
+		return port->get_mctrl(port);
+	return serial8250_do_get_mctrl(port);
+}
 
 void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {

include/linux/serial_8250.h

@@ -36,6 +36,7 @@ struct plat_serial8250_port {
 	void		(*set_termios)(struct uart_port *,
 			               struct ktermios *new,
 			               struct ktermios *old);
+	unsigned int	(*get_mctrl)(struct uart_port *);
 	int		(*handle_irq)(struct uart_port *);
 	void		(*pm)(struct uart_port *, unsigned int state,
 			      unsigned old);
@@ -148,6 +149,7 @@ extern int early_serial8250_setup(struct earlycon_device *device,
 					 const char *options);
 extern void serial8250_do_set_termios(struct uart_port *port,
 		struct ktermios *termios, struct ktermios *old);
+extern unsigned int serial8250_do_get_mctrl(struct uart_port *port);
 extern int serial8250_do_startup(struct uart_port *port);
 extern void serial8250_do_shutdown(struct uart_port *port);
 extern void serial8250_do_pm(struct uart_port *port, unsigned int state,

include/linux/serial_core.h

@@ -123,6 +123,7 @@ struct uart_port {
 	void			(*set_termios)(struct uart_port *,
 				               struct ktermios *new,
 				               struct ktermios *old);
+	unsigned int		(*get_mctrl)(struct uart_port *);
 	void			(*set_mctrl)(struct uart_port *, unsigned int);
 	int			(*startup)(struct uart_port *port);
 	void			(*shutdown)(struct uart_port *port);